首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15566篇
  免费   191篇
  国内免费   119篇
教育   10671篇
科学研究   2050篇
各国文化   112篇
体育   1354篇
综合类   11篇
文化理论   120篇
信息传播   1558篇
  2020年   211篇
  2019年   311篇
  2018年   429篇
  2017年   374篇
  2016年   386篇
  2015年   245篇
  2014年   320篇
  2013年   2653篇
  2012年   298篇
  2011年   340篇
  2010年   246篇
  2009年   243篇
  2008年   254篇
  2007年   286篇
  2006年   278篇
  2005年   271篇
  2004年   255篇
  2003年   248篇
  2002年   240篇
  2001年   256篇
  2000年   274篇
  1999年   277篇
  1998年   143篇
  1997年   150篇
  1996年   184篇
  1995年   172篇
  1994年   132篇
  1993年   143篇
  1992年   216篇
  1991年   226篇
  1990年   231篇
  1989年   260篇
  1988年   212篇
  1987年   225篇
  1986年   220篇
  1985年   253篇
  1984年   223篇
  1983年   213篇
  1982年   176篇
  1981年   169篇
  1980年   157篇
  1979年   244篇
  1978年   190篇
  1977年   181篇
  1976年   148篇
  1975年   132篇
  1974年   152篇
  1973年   134篇
  1972年   108篇
  1971年   120篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
Nutraceuticals are nutritional medicines which are present in edible food items. Most of them are antioxidants with various other biological properties viz, anti inflammatory, anti atherogenic, anticancer, anti viral, anti aging properties etc. They are as simple as minerals like Se2+ to complex organic molecules such as glycyrrhizin (Ca2+, K+ salts of glycyrrhizic acid). They can prevent as well as cure various diseases. Most of the medical people are not aware of the importance of the nutraceuticals as such matters are not part of their text books. Many still think that vitamins are the major nutritional medicines. Actually other dietary principles like terpenes, carotenes, phytosterols, polyphenols, flavanoids, di and poly sulphides, their sulfoxides and their precursor amino acids are necessary to scavenge free radicals in the body which are reactive oxygen species to protect and maintain the vitamin levels in the body. They down regulate the activities of those enzymes which are increased in diseases and they increase those that remove oxidants and detoxify carcinogens. They are immune boosters too. Recently glucosinolates, non toxic alkaloids, certain proteins and even fiber are included in the list of nutraceuticals.  相似文献   
862.
This paper presents a new approach to science education that takes a path through sociocultural theory and into the ideas of Gloria Anzaldúa. We apply Anzaldúan theory to science education by illustrating it in action through various examples which explore the multidimensionality of teaching science with Latin@ students in various contexts including dual language settings. We present what it is to journey through transformation using examples from educators at various levels of science within the world of teaching science with Latin@ students in the U.S. Our examples illustrate how Latin@ students cross many cultural borders in Spanish, English, Latin@ home culture, school culture, and the world of scientific dialogue and content, and in doing so, go through tensions and transformations between dominant and non-dominant worlds, which should be acknowledged and better understood through Anzaldúan theory. Fundamentally, we present a transformative notion of Latin@ science learning as “living on the bridges” of many dialogic and cultural practices, and having to negotiate these in-between spaces, or “nepantla” (Anzaldu´a and Keating in Interviews, Psychology Press, London, 2000), where Latin@ students must contend with the fragmented and sometimes painful struggle of living in racialized reality amidst the demands of a dominant culture, and where transformation and healing are possible through the path of conocimiento. We advocate for teachers to become science teacher nepantler@s, who guide their students through nepantla, and into a new mestiz@ consciousness of science education.  相似文献   
863.
Diversity, multicultural education, equity, and social justice are dominant themes in cultural studies (Hall in Cultural dialogues in cultural studies. Routledge, New York, pp 261–274, 1996; Wallace 1994). Zeichner (Studying teacher education: The report of the AERA panel on research and teacher education. Lawrence Erlbaum Associates, Mahwah, pp 737–759, 2005) called for research studies of teacher educators because little research exists on teacher educators since the late 1980s. Thomson et al. (2001) identified essential elements needed in order for critical multiculturalism to be infused in teacher education programs. However, little is known about the commitment and experiences of science teacher educators infusing multicultural education, equity, and social justice into science teacher education programs. This paper examines twenty (20) Black science teacher educators’ teaching experiences as a result of their Blackness and the inclusion of multicultural education, equity, and social justice in their teaching. This qualitative case study of 20 Black science teacher educators found that some of them have attempted and stopped due to student evaluations and the need to gain promotion and tenure. Other participants were able to integrate diversity, multicultural education, equity and social justice in their courses because their colleagues were supportive. Still others continue to struggle with this infusion without the support of their colleagues, and others have stopped The investigators suggest that if science teacher educators are going to prepare science teachers for the twenty first century, then teacher candidates must be challenged to grapple with racial, ethnic, cultural, instructional, and curricular issues and what that must mean to teach science to US students in rural, urban, and suburban school contexts.  相似文献   
864.
Exposure to arsenic has been associated with several health hazards. Worldwide the main reason for chronic human intoxication with arsenic is intake of contaminated drinking water. Air acetylene type of atomic absorption spectrophotometer in combination with hydride generator accessory was used to analyze arsenic level in 25 water samples collected from 25 booster pumping stations and 313 water samples collected from tap water supply of 62 areas of Delhi. Results were analyzed using SPSS and Barlett’s Chi Square Test. Mean arsenic level detected in water samples collected from booster pumping stations was 0.00976 ppm (Range 0.000–0.017 ppm, Standard Deviation 0.006 and Standard error of Mean 0.00118). Maximum arsenic level (0.017 ppm) was found in water samples of booster pumping stations of Mehrauli, Punjabi Bagh and Ramjas Road. Mean arsenic level detected in samples collected from tap water supply was 0.013 ppm (Range 0–0.0430 ppm, Standard Deviation 0.00911 and Standard error of Mean 0.000515). In water samples of 42 areas arsenic level detected was exceeding WHO/EPA permissible limit of 0.01 ppm (10 ppb). The mean arsenic level detected in water samples of booster pumping station was within WHO/EPA permissible limit while mean arsenic level detected in tap water samples was marginally higher. Mixing of ground water and contamination through broken or leaking channel could be the possible reason of higher arsenic level in tap water. Continuous monitoring of quality of drinking water is required particularly in view of water contamination caused by industrial waste and uncontrolled ground water extraction.  相似文献   
865.
Relational Aggression, Overt Aggression, and Friendship   总被引:18,自引:1,他引:18  
This study ( n = 315 9–12-year-olds) was conducted to assess whether the social problems that relationally and overtly aggressive children typically experience in the peer group context are also exhibited in the dyadic, friendship context. The qualities of children's friendships (e.g., levels of intimacy) and of the importance of those qualities (e.g., the importance of intimacy) were assessed with self-report instruments adapted from past research. Results indicated that the friendships of relationally aggressive children were characterized by relatively high levels of intimacy, exclusivity/jealousy, and relational aggression within the friendship context. In contrast, the friendships of overtly aggressive children were characterized by engaging together in aggressive acts toward those outside the friendship. In addition, overtly aggressive children placed relatively high importance on these coalitional acts and on companionship with their friends. Implications for our understanding of aggressive children and for our knowledge of children's friendships are discussed.  相似文献   
866.
867.
The object of the study was to determine the major needs of students at the University of the Western Cape (U.W.C.). A second aim was to determine how students view the nature of the Centre for Student Counselling (C.S.C.). No needs assessments have previously been done on the U.W.C. campus and this lack of knowledge pertaining to the needs of students could have meant a misdirected focus in terms of the provision of counselling services.The study was done with a representative sample of students from all the year groups. Students were asked to fill in a questionnaire consisting of two parts. In Part I a student had to indicate how prevalent he thought a particular set of problems were on campus. In Part II he had to indicate whether he would have referred a friend to the C.S.C. with a particular problem.The results had indicated that problems were predominantly seen to be in the vocational-academic area and that students were more willing to refer fellow students to the C.S.C. with the above-mentioned problems than with problems of a more personal-social nature. Although the results were to be expected, it was emphasized that vocational-academic problems are often used as a smoke-screen and that counsellors should also be aware of underlying social-emotional problems.  相似文献   
868.
869.
870.
The purpose of this study was to examine whether an innovative, inclusive and integrated 12-week exercise, behaviour change and nutrition advice-based weight management programme could significantly improve the cardiovascular risk factors of overweight and obese men and women over the age of 35. One hundred and ninety-four men and 98 women (mean age?=?52.28?±?9.74 and 51.19?±?9.04) attending a community-based intervention delivered by Notts County Football in the Community over one year, took part in the study. Height (m), weight (kg), fitness (meters covered during a 6?min walk) and waist circumference (cm) were measured at weeks 1 and 12 as part of the intervention. Changes in body weight, waist circumference and fitness for men and women were measured by a 2-way repeated measures ANOVA, with significance set to p?<?0.05.Weight, waist circumference and fitness significantly improved over time in both men (4.96?kg, 6.29?cm, 70.22?m; p?<?0.05) and women (4.26?kg, 5.90?cm, 35.29?m; p?<?0.05). The results demonstrated that the FITC lead weight loss intervention was successful in significantly improving cardiovascular risk factors in both men and women. In particular, the weight loss reductions achieved were comparable to those seen in similar, more costly men-only programmes. This is the first study to demonstrate the efficacy of such an intervention in an inclusive, mixed gender programme and more specifically, in women.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号